This relates to graphics processing.
Aliasing is an artifact that results from undersampling of an image. It may appear as jagged lines or edges.
Anti-aliasing reduces aliasing. In three-dimensional graphics pipelines graphics are handled with very high resolution. During rendering, the color of each pixel to be displayed is determined. At this or a later stage anti-aliasing may be performed.
In sampling, a single value called a sample is chosen from a varying series of values. The more samples, the more accurately the rendering of a scene.
Coverage-Sampling Anti-Aliasing (CSAA) is an affordable high-quality anti-aliasing (AA) method, since it has more visibility samples (also called coverage samples) than color and depth samples. Per pixel, each visibility sample then “points” in to a small table of values, called a pixel's value table, where values can be colors, colors/depth pairs, colors/depths/stencil, etc. Since there are more visibility samples, the AA quality can be higher.
However, for pixels with more values than can fit in the table, some heuristic would be used to merge two values into one. Currently, it is not well known how this would be done.